Terminal Database login problem ( again )

[Mark J. Bailey]

kleiner at bu-tyng.bu.edu (Ken Kleiner) writes:

>In article <103961 at convex.convex.com> kemp at convex1.convex.com (Phil Kemp) writes:
>>
>>I caught the end of a thread last week about SCO UNIX failing to allow
>>logins due to corruption of the terminal database. This bug has bite
>>me twice now and I would like to know if anyone has further info on the
>>details of this corruption. The first time I tried to reboot I couldn't
>>get the system back up. I had to re-install from scratch. ( Well the
>>base system, anyway... ). The problem has re-occurred and I am not able
>>to check it out immediately. Please post as I'm not sure how well my
>>mail is going to work this week :-( ....
>>
>>Thanks for any help

>Hi,

>	Well, I came across that problem in an SCO class that I was
>	teaching.  All of a sudden, a student said that he couldn't
>	log in.  He was getting the error 'Cant Obtain Database Info
>	on this Terminal'.  It happened right after we tried
>	the 'mscreen' command (some were still in mscreen).  It seems that
>	there was a file called /etc/auth/system/ttys-t hanging around.
>	We renamed it to something else and everything worked fine after
>	that.  Is this a temp file of some sort built from 
>	/etc/auth/system/ttys?  

>	BTW, it only happens when you use mscreen.

>	Anybody else seen this?



>							-Ken

I have had the same problem for some time on SCO Unix 3.2.1 (shipped
with EAP ODT).  It occurs when the terminal database logging process
fails (somehow) and does not completely remove its temp files.  This
is documented in at least the ODT system admin's guide in the section
on error messages.

I contacted SCO about it and they are aware of it and are working on
a fix.  Aparently (IMHO), there is a flaw in their algorithm.  They 
had a fix disk for a while and then pulled it (I assume because of
continued problems).  This is all a part of the C2 security system.
In my experience with it, it occurs when several people are logging
in or out simultaneously.  The processes working with the ttys must
collide at a critical section and die prematurely.  Your experience
with it when using mscreen would likely create such a period of lots
of logging in processes.  I suspect that this is big on SCO's fix list.

When I posted to the net about a month ago, one reader sent me
the following shell script that I think he got from SCO as a temporary
fix (kludge) to cleanup when the garbage ttys-* files get left around.
I run it from cron every 30 minutes, and while I am still running into
this problem, at least every 30 minutes, it is being checked and cleared!
While there is a possibility of it running at the same time someone is
logging in, so far I have had no problems.  Beats driving 10 miles across 
town from home everytime it screws up.  I suppose one could add a little
to the front of the script to check for temp ttys-* that are older than,
say, 5 minutes.

You should contact SCO tech support and at least get on the list for
the fix.  I believe it will be an update to the C2 security system.

Hope this helps.  Thanks to Lance Ellinghouse for this fix!  It works!  :-)

Mark.

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>From uunet!sco!hermix!root Mon Jun 18 23:57:33 1990
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From: uunet!hermix!root (Superuser)
X-Mailer: SCO System V Mail (version 3.2)
To: mjbtn!mjb
Subject: Fix for problems with *-t files on TTYs
Date: Mon, 18 Jun 90 13:41:47 PDT
Message-Id:  <9006182041.aa01535 at hermix.UUCP>
Status: RO

Here is a fix that I put together for the problem of TTYs
database going down due to the *-t file being left there.
The script follows and then put a line in the root's crontab
to run this every now and then. This fix was given to me by 
SCO after MANY MANY complaints from eme. Have fun!

------- Cut here --------

#
# This is to fix the tty database when it gets a messed up
# 

if [ -f /etc/auth/system/ttys ]
then
   if [ -f /etc/auth/system/ttys-t ]
   then
      rm /etc/auth/system/ttys-t
   fi
   if [ -f /etc/auth/system/ttys-o ]
   then 
      rm /etc/auth/system/ttys-o
   fi
   exit
fi

if [ -f /etc/auth/system/ttys-o ]
then
   mv /etc/auth/system/ttys-o /etc/auth/system/ttys
   chown auth /etc/auth/system/ttys
   chgrp auth /etc/auth/system/ttys
   chmod 664 /etc/auth/system/ttys
   if [ -f /etc/auth/system/ttys-t ]
   then
      rm /etc/auth/system/ttys-t
   fi
   exit
fi

if [ -f /etc/auth/system/ttys-t ]
then
   mv /etc/auth/system/ttys-t /etc/auth/system/ttys
   chown auth /etc/auth/system/ttys
   chgrp auth /etc/auth/system/ttys
   chmod 664 /etc/auth/system/ttys
   exit
fi

------ Done ------

Have fun and enjoy! 
Lance Ellinghouse
Mark V Systems, Ltd.
E-mail: uunet!sco!hermix!lance
        hermix!lance at anes.ucla.edu

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